Abstract. Mangiferin, a flavonoid extracted from the mango tree, possesses anti-inflammatory, antibacterial, anti-herpes simplex and antitumor activity, and is able to affect immune function. The present study investigated the anticancer effects of mangiferin treatment on PC3 human prostate cancer cells, and the potential underlying mechanisms. In the present study, an MTT assay was used to analyze the proliferation of PC3 cells. Subsequently, flow cytometry and colorimetric assay kits were utilized to measure the PC3 cell apoptotic rate. The expression levels of B-cell lymphoma-2 (Bcl-2) and microRNA-182 (miR-182) were detected using western blot analysis and quantitative reverse transcription-polymerase chain reaction, respectively. Finally, miR-182 and anti-miR-182 were transfected into PC3 cells, which were used to investigate the effects of mangiferin. Mangiferin treatment reduced the proliferation of PC3 human prostate cancer cells in a concentration-and time-dependent manner. In addition, mangiferin was able to promote apoptosis and induce the caspase-3 activity of PC3 human prostate cancer cells. Mangiferin treatment was also able to significantly reduce Bcl-2 expression levels and enhance miR-182 expression in PC3 cells. Finally, it was observed that mangiferin inhibited proliferation and induced apoptosis in PC3 human prostate cancer cells, and this effect was correlated with downregulation of Bcl-2 and upregulation of miR-182.
IntroductionProstate cancer is a disease that affects older males, and is one of the most common malignant tumors amongst males in Europe (1). Previously, prostate cancer was observed relatively rarely in China; however, in recent years the incidence of prostate cancer and associated mortality rates have been increasing (1).In 2008, the worldwide standardized incidence rate of prostate cancer was 28.5/100,000 and the standardized mortality rate was 7.5/100,000 (2-4). Therefore, prostate cancer has become a significant area of research.Cell apoptosis may be inseparable from the development of prostate cancer. Apoptosis, or programmed cell death, differs from necrosis, the natural cell death process (5). Reduced apoptosis and increased proliferation are thought to be the primary mechanisms underlying the formation of the majority of tumors. Inhibition of apoptosis may also possess a significant role in the progression of prostate cancer, and B-cell lymphoma-2 (Bcl-2) is thought to be one of the most significant genes required for apoptosis (6).MicroRNAs (miRs) are a class of endogenously expressed non-protein encoding RNAs (2). Mature miRs are single-stranded and consist of ~22 nucleotides (7). Previous studies have indicated that miRs may be involved in human tumorigenesis and development. Numerous tumors exhibit alterations in miR expression levels, and these miRs may have a role in tumorigenesis, functioning as cancer genes or tumor suppressor genes (8). Casanova-Salas et al (9) demonstrated that miR-182 was a potential biomarker for prostate cancer diagnosis, prognosis predict...